descriptionIntended use: This SALSA® MLPA® probemix P241 MODY Mix 1 is an in vitro diagnostic (IVD)1 or research use only (RUO) assay for the detection of deletions or duplications in the human HNF4A, GCK, HNF1A, and HNF1B genes in order to confirm a potential cause and clinical diagnosis for Maturity-Onset Diabetes of the Young (MODY) type 1, 2, 3, and 5, respectively. Furthermore, it is intended for the detection of deletions in the human HNF1B gene in order to confirm a potential cause and clinical diagnosis for RCAD (Renal Cysts and Diabetes Syndrome).

This product can also be used for molecular genetic testing of at-risk family members/individuals. It is intended for use with human DNA extracted from peripheral blood. Deletions or duplications obtained with the P241 MODY probemix must be verified by another technique. In particular, deletions or duplications detected by only a single probe always require validation by another method. Most defects in the aforementioned genes are point mutations, none of which will be detected by MLPA. It is therefore recommended to use this SALSA MLPA probemix in combination with sequence analysis of the aforementioned genes. This assay is not intended to be used as standalone assays for clinical decisions. The results of this test are intended to be interpreted by a clinical molecular geneticist or equivalent.

1 Please note that this probemix is for In Vitro Diagnostic use (IVD) in the countries specified at the end of this product description. In all other countries, the product is for Research Use Only (RUO).

Clinical background: Maturity-Onset Diabetes of the Young (MODY) is a distinct form of non-insulin-dependent diabetes mellitus (NDDM, also known as type II diabetes). MODY has a dominant autosomal inheritance and generally develops in individuals under the age of 25 years. Of all diabetes patients, 1-5% suffer from MODY. As described below, 11 forms of MODY are identified. Each form is associated with one gene. MODY 1, 2 and 3 account for approximately 70% of the MODY cases. Pathogenic mutations in additional genes, for example ABCC8 and KCNJ11, have also been described. These additional subtypes together account for approximately 1% of MODY. More information is available at http://www.nature.com/ejhg/journal/v22/n9/full/ejhg201414a.html.

Renal Cysts and Diabetes Syndrome (RCAD) is an autosomal dominant disorder characterised by diabetes and nondiabetic renal disease resulting from abnormal renal development. Whole HNF1B gene deletions form a high proportion of RCAD cases. More information is available at https://omim.org/entry/137920.

MODY 1 is a result of defects in the hepatocyte nuclear factor-4-alpha (HNF4A) gene. The protein encoded by this gene regulates the expression of HNF1A. Probes for HNF4A are included in this P241 probemix. MODY 2 is caused by mutations in the glucokinase gene (GCK). Probes for GCK are included in this P241 probemix.MODY 3 is caused by defects in the HNF1 homeobox A gene (HNF1A). Probes for HNF1A are included in this P241 probemix.MODY 4 has been linked to defects in the pancreas/duodenum homeobox protein 1 gene (PDX1). Probes for PDX1 are included in the P357 probemix.MODY 5 has been associated with the HNF1 homeobox B gene (HNF1B). The gene is also associated with RCAD. Probes for HNF1B are included in this P241 probemix and in the P357 probemix.MODY 6 has been linked to defects in the NEUROD1 gene. Probes for NEUROD1 are included in the P357 probemix.MODY 7 is caused by mutations in the krüppel-like factor 11 gene (KLF11) on chromosome 2p25. Probes for KLF11 are included in the P357 probemix.MODY 8 has been associated with defects in carboxyl-ester lipase gene (CEL). Probes for CEL are included in the P357 probemix.MODY 9 is caused by defects in the paired box 4 gene (PAX4). Probes for PAX4 are included in the P357 probemix.MODY 10 has been linked to mutations in the insulin gene (INS). Probes for INS are included in the P357 probemix.MODY 11 has been linked to defects in the B lymphoid tyrosine kinase gene (BLK). No probes for BLK have been included in probemix P241 or probemix P357.

P241-E1 probemix content: The P241-E1 MODY Mix 1 probemix contains 52 MLPA probes with amplification products between 130 and 500 nt. It contains probes for the HNF4A, GCK, HNF1A, and HNF1B genes and is therefore specific for MODY 1, 2, 3, and 5. For the HNF4A gene, 12 probes are included, furthermore 11 for the GCK gene, 11 for the HNF1A gene, and 10 for the HNF1B gene. In addition, 8 reference probes are included in this probemix. The identity of the genes detected by the reference probes is available online (www.mlpa.com).

This probemix contains nine quality control fragments generating amplification products between 64 and 105 nt: four DNA Quantity Fragments (Q-fragments), three DNA Denaturation Fragments (D-fragments), and one chromosome X and one chromosome Y-specific fragment (Table 1). The Q-fragments are only visible when less than 100 ng sample DNA is used. Low signal of the 88 or 96 nt fragment indicates incomplete DNA denaturation. More information on how to interpret observations on these control fragments can be found in the MLPA General Protocol.

product historyversion E1: A promoter and exon 1 probes for HNF4A have been added. Also, four HNF4A probes, two GCK probes, one HNF1B probe and two reference probes have been replaced.version D2: One reference probe has been replaced.version D1: As compared to version B1, 8 reference probes have been included. Two HNF1A and four HNF1B probes have been replaced. The 88 and 96 nt control fragments have been replaced (QDX2). version B1: Several probes for the HNF1A genes have been added.